Plastic electronics can slash cost of solar panels

Last Updated: Sat, Apr 03, 2010 07:40 hrs

A new technique developed by engineers for producing power-conducting plastics could slash the cost of making solar panels, say researchers.

With mounting concerns about global warming and energy demand, plastics could represent a low-cost alternative to indium tin oxide (ITO), an expensive conducting material currently used in solar panels, according to the researchers.

'Conductive polymers (plastics) have been around for a long time, but processing them to make something useful degraded their ability to conduct electricity,' said Yueh-Lin Loo, associate professor of chemical engineering at Princeton University, who led the research team.

'We have figured out how to avoid this trade-off. We can shape the plastics into a useful form while maintaining high conductivity,' Yueh-Lin Loo added.

The area of research, known as 'organic electronics' because plastics are carbon-based like living creatures, holds promise for producing new types of electronic devices and new ways of manufacturing existing technologies, but has been hampered by the mysterious loss of conductivity associated with moldable plastics.

'People didn't understand what was happening,' said Loo, who co-wrote the paper. 'We discovered that in making the polymers moldable, their structures are trapped in a rigid form, which prevented electrical current from travelling through them.'

Once they understood the underlying problem, Loo and her colleagues developed a way to relax the structure of the plastics by treating them with an acid after they were processed into the desired form.

Using the method, they were able to make a plastic transistor, a fundamental component of electronics that is used to amplify and switch electronic signals.

They produced the electrodes of the transistor by printing the plastic onto a surface, a fast and cheap method similar to the way an ink-jet printer produces a pattern on a piece of paper.

Loo said the technique potentially could be scaled up for mass production presses akin to those used to print newspapers.

'Being able to essentially paint on electronics is a big deal,' Loo said. 'You could distribute the plastics in cartridges the way printer ink is sold, and you wouldn't need exotic machines to print the patterns.'

By allowing plastic solar cells to be manufactured using low-cost printing techniques and by replacing ITO as the primary conducting material, the plastics the team developed hold potential for lowering the cost of solar panels, said a Princeton release.

These findings were published online in the March issue of the Proceedings of the National Academy of Sciences.

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